the best suggestion would be to contact a design professional or a cabinet company to assist you, as a project of this nature could take hours to design and refine and then the production time for the design needs to be over seen by a knowledgable person good luck....this is a for pay type of design issue

Is this wall above ground or in a basement? Water penetration isn't good so you need to find an inspector (home insp or mold insp) who can examine your roof, gutters, siding and who has an "thermal imaging camera". Lesley is on the mark about mold which needs moisture to grow. So, have a pro get up on your roof especially in the area near the water stains. Another tip, get it done before winter and bank on tearing out that wall to treat the wood studs with bleach to kill anything.

You might consider also the space a round table has compared to a rectangular one. Usually, the round table of a 5 ft. diameter will not have a lot of room for 6 people to sit. It will be a little snug. Serving dishes will need to fit on the center of the table or off of the table. The rectangular table would offer more spacious seating for 6. Is it too large for your room? What are the dimensions of your dining room? (x ft. by y ft) As to your color palette, the contrast of black with other white furniture is interesting. Also, the green with the black and white could be quite unifying.

You've got a great space here, and there's so much you can do with it! Do you know what style you're looking to achieve? If you've already got a red and white colour scheme going in your kitchen, you can always opt for this in the living room. Sometimes grey can make the room look a little dark, so it's always worth investing in a white base, and build from there. Maybe change the colour of the curtains to something a little lighter and richer?